1. Field of the Invention
The present invention relates to a load line type phase displacement unit, and in particular, to an improved load line type phase displacement unit which is capable of reducing the time which is required for designing the system and of increasing system fabrication efficiency by simply adjusting a phase difference of an input signal by adjusting the length of a stub after the impedances of a main line and a stub are made identical with a characteristic impedance.
2. Description of the Prior Art
Generally, in accordance with the recommendation by IEEE, a dynamic phase arrangement antenna is provided with a phase displacement unit of a main line in accordance with a method for controlling a steering direction and position of an antenna beam in a Ka band width (for example, 27.about.40Ghz) among microwave bands.
The above-described phase displacement unit of a main line in accordance with the IEEE recommended method is implemented by varying the impedance of the main line and adjusting the length and impedance of a stub.
However, in the conventional phase displacement unit, since the impedance of the main line, the impedance of the stub and the impedance of the input signal are not identical, in a T-junction portion, namely, in the millimeter wave in which the electrical characteristic of the portion where the characteristic impedance and the impedance of the main line are different (Z.sub.0 .noteq.Z.sub.c), the decoding of the non-continuity is not made easily.
In addition, since it is impossible to minimize the parasitic components, the malfunction may occur in the Ka band width, and the resonant phenomenon may occur in the electrical characteristic of a switching device and micro strip. Furthermore, a big insertion loss and a phase error may occur due to the loss in a predetermined frequency band width of a design specification.